Why are Chiles Spicy?

Am I the only chile head who has wondered why chiles are spicy? Finally, we have an answer to that question thanks to Josh Tewksbury of the University of Washington. Late last summer, he published a paper entitled "The evolutionary ecology of pungency in wild chilies" in Proceedings of the National Academy of Sciences. This paper theorizes that certain bugs are vectors for a Fusarium fungus that destroys the seeds of chile peppers and capsaicinoids are a chemical defense against the seed-destroying fungi.